*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    /* 100%窗口高度 */
    height: 100vh;
    /* 弹性布局 水平垂直居中 */
    display: flex;
    justify-content: center;
    align-items: center;
    /* 渐变背景 */
    background-color: #fff;
}
.container{
    /* 相对定位 */
    position: relative;
    background-color: #fff;
    width: 650px;
    height: 420px;
    border-radius: 5px;
}
.form-box{
    /* 绝对定位 */
    position: absolute;
    top: -10%;
    left: 5%;
    background-color: aquamarine;
    width: 320px;
    height: 500px;
    /* 圆形边框 */
    border-radius: 5px;
    /* 弹性布局 居中 */
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2;
    /* 动画时间和方式 */
    transition: 0.5s ease-in-out;
}
.register-box,.login-box{
    display: flex;
    /* 顺序排列 */
    flex-direction: column;
    align-items: center;
    width: 100%;
}
.hidden{
    /* 隐藏 */
    display: none;
    transition: 0.5s;
}
h1{
    text-align: center;
    margin-bottom: 25px;
    /* 大写 */
    text-transform: uppercase;
    /* 字间距 */
    letter-spacing: 5px;
}
input{
     background-color: transparent;
     width: 70%;
     color: #fff;
     border: none;
     border-bottom: 1px solid rgba(255, 255, 255, 0.4);
     padding: 10px 0;
     text-indent: 10px;
     margin: 8px 0;
     font-size: 14px;
     letter-spacing: 2px;
}
input::placeholder{
    color: #fff;
}
input::focus{
    color: #a262ae;
    outline: none;
    border-bottom: 1px solid #a262ad80;
    transition: 0.5s; 
}
input::focus::placeholder{
    opacity: 0;
}
.form-box button{
   width: 70%;
   height: 45%;
   margin-top: 35px;
   background-color: #f6f6f6;
   outline: none;
   border-radius: 8px;
   padding: 13px;
   letter-spacing: 2px;
   border: none;
   cursor: pointer;
}
.box{
    width: 50%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: absolute;
    top: 50%;
    /* 竖直方向移动一半 */
    transform: translateY(-50%);
}
.box.left{
    left: -2%;
}
.box.right{
    right: -2%;
}
.box h2{
    color: #a262ae;
    font-size: 25px;
    font-weight: bold;
    letter-spacing: 3px;
    text-align: center;
    margin-bottom: 4px;
}
.box p{
    color: #a262ae;
    font-size: 12px;
    text-align: center;
}
.box button{
    margin-top: 3%;
    background-color: #fff;
    color: #a262ae;
    border: 1px solid #f6f6f6;
    padding: 6px 12px;
    border-radius: 5px;
    letter-spacing: 1px;
    outline: none;
    cursor: pointer;
}
.box button:hover{
    background-color: #fff;
    color: #a262ae;
}